摘要
To tackle the key-exposure problem in signature settings,this paper introduces a new cryptographic primitive named threshold key-insulated signature(TKIS) and proposes a concrete TKIS scheme.For a TKIS system,at least k out of n helpers are needed to update a user's temporary private key.On the one hand,even if up to k 1 helpers are compromised in addition to the exposure of any of temporary private keys,security of the non-exposed periods is still assured.On the other hand,even if all the n helpers are compromised,we can still ensure the security of all periods as long as none of temporary private keys is exposed.Compared with traditional key-insulated signature(KIS) schemes,the proposed TKIS scheme not only greatly enhances the security of the system,but also provides flexibility and efficiency.
To tackle the key-exposure problem in signature settings, this paper introduces a new cryptographic primitive named threshold key-insulated signature （TKIS） and proposes a concrete TKIS scheme. For a TKIS system, at least k out of n helpers are needed to update a user＇s temporary private key. On the one hand, even if up to k-1 helpers are compromised in addition to the exposure of any of temporary private keys, security of the non-exposed periods is still assured. On the other hand, even if all the n helpers are compromised, we can still ensure the security of all periods as long as none of temporary private keys is exposed. Compared with traditional key-insulated signature （KIS） schemes, the proposed TKIS scheme not only greatly enhances the security of the system, but also provides flexibility and efficiency.
基金
the National Natural Science Foundation of China (Nos.60970111,60903189 and 60903020)
the National High Technology Research and Development Program (863) of China (No.2009AA01Z418)
the National Basic Research Program (973) of China(No.2007CB311201)
